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RE: Nitro models pusher Bobcat?
I've got a dubro extension of between my engine and muffler, which with my fancy deflector puts the exhaust core just outside the prop arc.....As soon as it warms up another 30 or 40 degrees, I'll fire it up and see how much mess it makes, or hopefully, doesn't make..........
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RE: Nitro models pusher Bobcat?
Yes Joe
I am running an O.S. 91 on mine. Pusher engines carburetors are almost imposable to set on the ground so an in flight needle-valve is a must. This setup is great as a turbine trainer for people working on their waiver. Johnny |
RE: Nitro models pusher Bobcat?
Hey Johnny...what size 3 blade are you running on that .91?....any idea what top speed is?
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RE: Nitro models pusher Bobcat?
ORIGINAL: johnnyjet Pusher engines carburetors are almost imposable to set on the ground so an in flight needle-valve is a must. |
RE: Nitro models pusher Bobcat?
ORIGINAL: AGR413 ORIGINAL: johnnyjet Btw the engine will never know the direction the exhaust exits. AGR, I read about your problem with your backpressure/Tower .75/richness issue. I have run the Tower .75 in this plane for about 100 flights with no issues like that. I'd have to say that possibly your engine may be different in some manner or your tank configuration is not set up for this type of application. I suggested the use of a 2oz hopper as well. You really shouldn't have this problem, it's not a good one! Anyway, hope you worked it out regardless. |
RE: Nitro models pusher Bobcat?
Hey guys,
Does anyone know if RObart makes a pneumatic set of retracts that fit the Bobcat ? thanks. |
RE: Nitro models pusher Bobcat?
I have a set of their air up/ spring down #530s on order, I am not sure about the depth. I should take delivery in 2 weeks, they are a new item for Robart.
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RE: Nitro models pusher Bobcat?
AGR413
Einstein. Its called cooling airflow. You are comparing apples to oranges with the O.S. engine to the tower one. I am not going to waste additional time on this subject. Johnny |
RE: Nitro models pusher Bobcat?
Hi
CrashPro It’s a Master Airscrew 3-Bladed 14x7 Pusher Prop cut down to fit. With the gear pulled up the speed is insane. I will check my eagle tree for the recorded speed tonight. Johnny |
RE: Nitro models pusher Bobcat?
johnnyjet, which 91 are you running, and where did you get the inflight mixture control unit ?
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RE: Nitro models pusher Bobcat?
ORIGINAL: jroth I have a set of their air up/ spring down #530s on order, I am not sure about the depth. I should take delivery in 2 weeks, they are a new item for Robart. I would be careful to measure the thickness of the wing at the root and go a bit foward of where they will in the wing there as the wing thins as you go out. I would think that as long as the gear are 1" - 2" behind the CG you'd be OK... Bob |
RE: Nitro models pusher Bobcat?
i3dm, sent you a pm about mixture control. Bob
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RE: Nitro models pusher Bobcat?
ORIGINAL: johnnyjet AGR413 Einstein. Its called cooling airflow. You are comparing apples to oranges with the O.S. engine to the tower one. I am not going to waste additional time on this subject. Johnny You are the god of glow, are you happy now? Get off your pretentious passive/aggressive soap box and re-read the post. It was a toungue in cheek response to you taking yourself waaay to serious. I never intended to compare your high falutin OS to my lowely little Tower ok? Do yourself a favor, get a wind meter and an aircompressor and figure out what the distance is from the wind meter to achieve flight velocity and use that to blow air at the exhaust outlet. You might actually learn something. Now I'm quite certain you will have some other pretentious comback to this post, however my patience is at it's end with this subject as well and Jeves says I am late for my charity meeting. On a serious note: Dragon, I appreciate your comments I actually bought a 2 oz hopper tank and decided not to use it. Changing the angle of the exhaust to the airflow fixes the problem so that is an easy fix. It became very apparent that I was onto to problem when the first exhaust deflector blew off in flight and the condition immediately returned. In retrospect I consulted with an older wiser modeler when I was working on this problem. He was at the field, witnessed my findings and even participated in working through the problem. He was very surprised on the finding and mentioned that most pusher systems end up being tuned slightly lean on the ground for proper in-flight mixture to be achieved......hmmmmm. However, I want an engine I can adjust slightly rich on the ground and rely on that setting in the air when the engine unloads. Go figure. |
RE: Nitro models pusher Bobcat?
OK i talked to Robart here is what they say:
600P is a new low profile pneumatic set made for 2-5lb plane, only 3\4" tall, but will only take wire gear, not struts. http://www.robart.com/retracts/2-5lbPneu.aspx 510 set is 1+1/8" tall, spring down and can take struts, and is made for 6-12 pounds of plane. im thinking about getting a set of 510's for my Bobcat, with Robostruts, and if need be they will be protruding 1/8" out of the wing. What do you guys think about this ? http://www.robart.com/retracts/6-12lb510.aspx Also, who knows which robostruts would fit ? thanks guys. |
RE: Nitro models pusher Bobcat?
I just found that the 530RS are 1" tall and can take robostrtus.
http://www.robart.com/retracts/8-18lb530.aspx What do you guys think ? which is best ? |
RE: Nitro models pusher Bobcat?
I'm thinkin of just flying it as is and retrofitting the retracts when the regular gear rips out. At which time I'll be interested in whatever i3dm used.
What do you guys think? |
RE: Nitro models pusher Bobcat?
ORIGINAL: AGR413 ORIGINAL: johnnyjet AGR413 Einstein. Its called cooling airflow. You are comparing apples to oranges with the O.S. engine to the tower one. I am not going to waste additional time on this subject. Johnny You are the god of glow, are you happy now? Get off your pretentious passive/aggressive soap box and re-read the post. It was a toungue in cheek response to you taking yourself waaay to serious. I never intended to compare your high falutin OS to my lowely little Tower ok? Do yourself a favor, get a wind meter and an aircompressor and figure out what the distance is from the wind meter to achieve flight velocity and use that to blow air at the exhaust outlet. You might actually learn something. Now I'm quite certain you will have some other pretentious comback to this post, however my patience is at it's end with this subject as well and Jeves says I am late for my charity meeting. On a serious note: Dragon, I appreciate your comments I actually bought a 2 oz hopper tank and decided not to use it. Changing the angle of the exhaust to the airflow fixes the problem so that is an easy fix. It became very apparent that I was onto to problem when the first exhaust deflector blew off in flight and the condition immediately returned. In retrospect I consulted with an older wiser modeler when I was working on this problem. He was at the field, witnessed my findings and even participated in working through the problem. He was very surprised on the finding and mentioned that most pusher systems end up being tuned slightly lean on the ground for proper in-flight mixture to be achieved......hmmmmm. However, I want an engine I can adjust slightly rich on the ground and rely on that setting in the air when the engine unloads. Go figure. AGR413 My job is done. You just won my case. Thanks Johnny |
RE: Nitro models pusher Bobcat?
ORIGINAL: johnnyjet Yes Joe I am running an O.S. 91 on mine. Pusher engines carburetors are almost imposable to set on the ground so an in flight needle-valve is a must. This setup is great as a turbine trainer for people working on their waiver. Johnny I have a JETT BSE .50 no problem with needle-valve. |
RE: Nitro models pusher Bobcat?
Has anyone flow the Bobcat on a turbine yet? Maybe I missed it, there are some many pages to read here. Maybe a video link too? Thanks!
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RE: Nitro models pusher Bobcat?
ORIGINAL: johnnyjet ORIGINAL: AGR413 ORIGINAL: johnnyjet AGR413 Einstein. Its called cooling airflow. You are comparing apples to oranges with the O.S. engine to the tower one. I am not going to waste additional time on this subject. Johnny You are the god of glow, are you happy now? Get off your pretentious passive/aggressive soap box and re-read the post. It was a toungue in cheek response to you taking yourself waaay to serious. I never intended to compare your high falutin OS to my lowely little Tower ok? Do yourself a favor, get a wind meter and an aircompressor and figure out what the distance is from the wind meter to achieve flight velocity and use that to blow air at the exhaust outlet. You might actually learn something. Now I'm quite certain you will have some other pretentious comback to this post, however my patience is at it's end with this subject as well and Jeves says I am late for my charity meeting. On a serious note: Dragon, I appreciate your comments I actually bought a 2 oz hopper tank and decided not to use it. Changing the angle of the exhaust to the airflow fixes the problem so that is an easy fix. It became very apparent that I was onto to problem when the first exhaust deflector blew off in flight and the condition immediately returned. In retrospect I consulted with an older wiser modeler when I was working on this problem. He was at the field, witnessed my findings and even participated in working through the problem. He was very surprised on the finding and mentioned that most pusher systems end up being tuned slightly lean on the ground for proper in-flight mixture to be achieved......hmmmmm. However, I want an engine I can adjust slightly rich on the ground and rely on that setting in the air when the engine unloads. Go figure. AGR413 My job is done. You just won my case. Thanks Johnny |
RE: Nitro models pusher Bobcat?
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RE: Nitro models pusher Bobcat?
ORIGINAL: Crazy4Flight ORIGINAL: johnnyjet Yes Joe I am running an O.S. 91 on mine. Pusher engines carburetors are almost imposable to set on the ground so an in flight needle-valve is a must. This setup is great as a turbine trainer for people working on their waiver. Johnny I have a JETT BSE .50 no problem with needle-valve. i use in flight needle-valve to get the very last bit of performance out. johnny |
RE: Nitro models pusher Bobcat?
Rather than fitting the muffler with a additional "header" to deflect exhaust, why not use a "boloney" type cut used on motorcycle pipes. On the outlet just measure up about 5/16" an cut it at an angle and face the long end towards the front. Joe
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RE: Nitro models pusher Bobcat?
Should be getting the bobcat delivered next week.. i decided to go with my old picco 45 with a tuned pipe it should do fairly well if not ill just get the tower .75 but ill keep ya guys posted on how the picco does.
Joe |
RE: Nitro models pusher Bobcat?
iam using a deans whip antanna from lhs. about 10 bucks
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